/*
 *
 * Copyright 2015 gRPC authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

#include <stdio.h>
#include <string.h>

#include <grpc/grpc.h>
#include <grpc/grpc_security.h>
#include <grpc/slice.h>
#include <grpc/support/alloc.h>
#include <grpc/support/log.h>
#include <grpc/support/sync.h>
#include <grpcpp/security/credentials.h>

#include "src/core/lib/iomgr/error.h"
#include "src/core/lib/iomgr/load_file.h"
#include "src/core/lib/security/credentials/credentials.h"
#include "src/core/lib/security/util/json_util.h"
#include "src/cpp/client/secure_credentials.h"
#include "test/core/security/oauth2_utils.h"
#include "test/core/util/cmdline.h"

static grpc_call_credentials* create_sts_creds(const char* json_file_path) {
  grpc::experimental::StsCredentialsOptions options;
  if (strlen(json_file_path) == 0) {
    auto status = grpc::experimental::StsCredentialsOptionsFromEnv(&options);
    if (!status.ok()) {
      gpr_log(GPR_ERROR, "%s", status.error_message().c_str());
      return nullptr;
    }
  } else {
    grpc_slice sts_options_slice;
    GPR_ASSERT(GRPC_LOG_IF_ERROR(
        "load_file", grpc_load_file(json_file_path, 1, &sts_options_slice)));
    auto status = grpc::experimental::StsCredentialsOptionsFromJson(
        reinterpret_cast<const char*>(GRPC_SLICE_START_PTR(sts_options_slice)),
        &options);
    gpr_slice_unref(sts_options_slice);
    if (!status.ok()) {
      gpr_log(GPR_ERROR, "%s", status.error_message().c_str());
      return nullptr;
    }
  }
  grpc_sts_credentials_options opts =
      grpc::experimental::StsCredentialsCppToCoreOptions(options);
  grpc_call_credentials* result = grpc_sts_credentials_create(&opts, nullptr);
  return result;
}

static grpc_call_credentials* create_refresh_token_creds(
    const char* json_refresh_token_file_path) {
  grpc_slice refresh_token;
  GPR_ASSERT(GRPC_LOG_IF_ERROR(
      "load_file",
      grpc_load_file(json_refresh_token_file_path, 1, &refresh_token)));
  grpc_call_credentials* result = grpc_google_refresh_token_credentials_create(
      reinterpret_cast<const char*> GRPC_SLICE_START_PTR(refresh_token),
      nullptr);
  gpr_slice_unref(refresh_token);
  return result;
}

int main(int argc, char** argv) {
  grpc_call_credentials* creds = nullptr;
  const char* json_sts_options_file_path = nullptr;
  const char* json_refresh_token_file_path = nullptr;
  char* token = nullptr;
  int use_gce = 0;
  gpr_cmdline* cl = gpr_cmdline_create("fetch_oauth2");
  gpr_cmdline_add_string(cl, "json_refresh_token",
                         "File path of the json refresh token.",
                         &json_refresh_token_file_path);
  gpr_cmdline_add_string(
      cl, "json_sts_options",
      "File path of the json sts options. If the path is empty, the program "
      "will attempt to use the $STS_CREDENTIALS environment variable to access "
      "a file containing the options.",
      &json_sts_options_file_path);
  gpr_cmdline_add_flag(
      cl, "gce",
      "Get a token from the GCE metadata server (only works in GCE).",
      &use_gce);
  gpr_cmdline_parse(cl, argc, argv);

  grpc_init();

  if (json_sts_options_file_path != nullptr &&
      json_refresh_token_file_path != nullptr) {
    gpr_log(
        GPR_ERROR,
        "--json_sts_options and --json_refresh_token are mutually exclusive.");
    exit(1);
  }

  if (use_gce) {
    if (json_sts_options_file_path != nullptr ||
        json_refresh_token_file_path != nullptr) {
      gpr_log(GPR_INFO,
              "Ignoring json refresh token or sts options to get a token from "
              "the GCE metadata server.");
    }
    creds = grpc_google_compute_engine_credentials_create(nullptr);
    if (creds == nullptr) {
      gpr_log(GPR_ERROR, "Could not create gce credentials.");
      exit(1);
    }
  } else if (json_refresh_token_file_path != nullptr) {
    creds = create_refresh_token_creds(json_refresh_token_file_path);
    if (creds == nullptr) {
      gpr_log(GPR_ERROR,
              "Could not create refresh token creds. %s does probably not "
              "contain a valid json refresh token.",
              json_refresh_token_file_path);
      exit(1);
    }
  } else if (json_sts_options_file_path != nullptr) {
    creds = create_sts_creds(json_sts_options_file_path);
    if (creds == nullptr) {
      gpr_log(GPR_ERROR,
              "Could not create sts creds. %s does probably not contain a "
              "valid json for sts options.",
              json_sts_options_file_path);
      exit(1);
    }
  } else {
    gpr_log(
        GPR_ERROR,
        "Missing --gce, --json_sts_options, or --json_refresh_token option.");
    exit(1);
  }
  GPR_ASSERT(creds != nullptr);

  token = grpc_test_fetch_oauth2_token_with_credentials(creds);
  if (token != nullptr) {
    printf("Got token: %s.\n", token);
    gpr_free(token);
  }
  grpc_call_credentials_release(creds);
  gpr_cmdline_destroy(cl);
  grpc_shutdown();
  return 0;
}